Some conventional buttons, sliders, dials and other controls provide haptic feedback to a user. Such devices may provide a user with system status information. For example, an input device, such as a linear slider with minimum and maximum stops at each end, can communicate to a user the speed of an assembly line without the user having to actually observe the assembly line. When the slider is at a minimum stop, the assembly line is at its slowest speed; when at the maximum stop, the assembly line is at the fastest speed. The stops may be fixed during construction of the device or may be implemented with an actuator.
A single system may utilize a plurality of input devices to control the system. Each input device can serve as an individual control node that has the ability to control a function of the system. Typically, the input devices are located at various positions around the corresponding system for convenient interfacing with a system user.
For example, a room may have two doorways with a light switch adjacent to each doorway. As another example, an audio-visual component, such as a television, may have a volume or channel selector on the faceplate of the component and on a remote control. As still another example, a manufacturing line may have several start/stop switches. As yet another example, a security or fire alarm system may have an access panel near each of several entrances. When multiple nodes are present to control the same function of a system, a problem may arise when a user changes the setting for that function at one control node and the remaining control nodes do not reflect the change in the setting.